The field of this invention relates to the locating of one or more tiny holes within a block of material and principally to the locating of the holes within a block of plastic.
The subject matter of the present invention is to be discussed in conjunction with the field of medicine. However, it is to be understood that the subject matter of this invention could be utilized in numerous other fields, many of which may even be unknown to the inventor. The contemplated field of utility of this invention is directed to obtaining of an orifice member which provides for a restricted flow of a liquid through this orifice member. This restriction of flow can be of particular advantage within the medical field or within any other field where a restricted flow would be desirable.
In the constructing of any liquid conducting orifice, the side wall of the orifice would frictionally resist the flow of the liquid through the orifice. Normally, it is the intention to decrease this restriction so that the liquid can flow through the orifice with the minimum amount of resistance, therefore, a minimal amount of energy loss. However, this restriction to the flow of a liquid through an orifice can be utilized to advantage in certain environments.
The smaller the orifice, the greater the restriction. Also, the longer the orifice, the greater the restriction. If the orifice size is a thousandth of an inch or less, and the orifice separates a pair of fluid mediums with one fluid medium being at a pressure differential greater than the other, then that restriction could be utilized to maintain a certain pressure differential relationship between the two fluid mediums. There is a problem with a single orifice in that not much flow is permitted. Therefore, it is common to utilize a mass of orifices, all of which have the same size and which have the same amount of restriction. It is this mass of orifices that more effectively control and maintain the established pressure differential.
Within the field of medicine, a common disease in conjunction with eyes is glaucoma. Within the eyeball is located a liquid. This liquid is under pressure with a common pressure being approximately twenty millimeters of mercury. In glaucoma, this pressure increases and if the pressure gets too severe, the patient can actually go blind.
In the past, there have been different techniques in order to relieve this excessive pressure. A vast amount of money is spent each year on drops that are to be placed onto the eye that are minimally effective. Additionally, there have been numerous surgical techniques in order to relieve this pressure. One of the most common surgical techniques is merely to cut a hole into the eyeball which provides an outlet for some of the liquid contained in the eyeball thereby relieving the pressure. This hole is then sutured. The disadvantage of this technique is that initially the pressure of the liquid in the eyeball is decreased below the desired level to atmospheric pressure. As time goes on, the pressure will again build up back to its original level which will require a duplicating of the surgical technique.
To overcome the disadvantage of this technique, there has been manufactured a valve assembly which is to be mounted in conjunction with the eyeball and located within the hole cut into the eyeball. It is the function of the valve to be activated if a certain pressure level is exceeded and provide an escape route for some of the liquid contained within the eyeball thereby releasing the pressure. The disadvantage to this valve is that it frequently malfunctions thereby requiring replacement or complete removal of this valve unit.
Another known device has to do with utilizing a balloon operating pump as opposed to a valve. This balloon operated pump is to release liquid when the pressure is applied to the balloon. This pressure is to be applied by the natural blinking process of a human being or is to be applied by manual rubbing of one's eye. However, the patient is not sensitive to increased eye pressure, therefore, is not able to determine when it is desirable to operate the pump. Again, this type of unit is not free from malfunction although, prior to the present invention, is probably the best device available to relieve accumulated liquid pressure from the interior of an eyeball.
The present inventor discovered that if a tiny block of plastic could be manufactured with a mass of tiny, through openings, and this block of material was installed in conjunction with a hole extending into the interior of an eyeball, that depending on the size of these openings, a pressure differential can be established between the interior of the eyeball and the ambient which could be maintained without utilizing any moving parts. By varying the size of these holes, this pressure differential could also be varied. As the pressure increases, the amount of flow through the orifices increases, thereby decreasing the pressure. This is a desirable feature since not all people have the same liquid pressure within the interior of the eyeball. Therefore, if the size of the orifices could be precisely controlled, a custom designed liquid relief passage arrangement could be manufactured for that particular individual. The liquid that is conducted from the interior of the eyeball to the exterior of the eyeball is discharged naturally through the waste disposal system of the human being.
It has been impossible in the past to manufacture a block of material which had a mass of precisely sized, tiny openings. Small openings can be formed within a block of material, such as plastic, by the utilizing of a laser. However, lasers cannot, at present, make the openings that are required by the present invention as the minimal size of opening that can be formed by the laser is still too large or not of sufficient length. Therefore, another method had to be arrived at to manufacture such small openings of adequate length.
It is to be reiterated that the method of the present invention can be used to manufacture articles which are usable in other fields of endeavor. One example would be in the making of contact lenses for the eye. One of the inherent problems of a contact lens is that liquid and oxygen is normally blocked by the lens so there is no way for fluid from the exterior surface of the eyeball to penetrate to the interior surface of the lens. If a lens was manufactured in accordance with the method of the present invention, there would be a mass of tiny holes, or through openings, formed within the lens which would permit this liquid and oxygen to be conducted to the interior surface of the lens. This mass of tiny holes would not interfere with the normal vision of the lens.